Endohedral metallofullerenes are spherical fullerene carbon cages confining one or more metal atoms in their interior spaces. Several promising biomedical applications that exploit the special properties of metallofullerenes are being developed, including diagnostic and imaging agents (magnetic resonance imaging (MRI) contrast agents, X-ray contrast agents, radiotracers), therapeutic nuclear medicine, antioxidants and biosensors. In our development of Gd-containing endohedral metallofullerenes as paramagentic MRI contrast agents, we recognized the need to recover all of the metallofullerenes, not just the soluble Gd@C82 metallofullerenes which comprise only 5-10% of the sublimable Gd endohedral metallofullerenes produced by the carbon arc process. In Phase II we will use our new advances in the areas of metallofullerene production and post-production processing to both increase the yield of generated metallofullerenes and to separate and purify the large majority of Gd endohedrals that the current processes cannot access, thereby increasing the yield of useful products by over a factor of ten. Improved production apparatus will be used to manufacture greater amounts of metallofullerene raw materials. Scalable processing based on a chemical redox strategy will be implemented to separate all of the available Gd metallofullerenes differentiate them into different classes based on their physical and chemical properties. Careful analytical evaluation of the obtained Gd metallofullerene fractions will be performed. These advances will benefit the development of MRI contrast applications based on metallofullerenes by generating more raw materials while separating the mixture of produced metallofullerenes into useful, homogeneous fractions.